1. In 1804, the Lewis and Clark Expedition traveled through what is now South Dakota on August 17. They camped near present-day Chamberlain and named the area "Crow Creek."

2. On August 17, 1876, the first organized settlement in the Black Hills was established when prospectors moved into the area and created a community that would eventually become the city of Deadwood.

3. In 1940, the Oahe Dam was completed on the Missouri River near Pierre, South Dakota. The dam created Lake Oahe, which is one of the largest man-made reservoirs in the United States and provides hydroelectric power, flood control, and irrigation water.

4. August 17, 1971, was a significant date for the Pine Ridge Indian Reservation. That day, the Oglala Sioux Tribal Council declared their intent to take control of their own affairs and establish a government that would be recognized by the federal government.

5. South Dakota celebrated its Centennial on August 17, 1989. The state marked its 100th anniversary with a year-long celebration that included parades, music festivals, historical reenactments, and other events.